drivers/iio/adc/mcp320x.c

   1 /*
   2  * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
   3  * Copyright (C) 2014 Rose Technology
   4  *         Allan Bendorff Jensen <abj@rosetechnology.dk>
   5  *         Soren Andersen <san@rosetechnology.dk>
   6  *
   7  * Driver for following ADC chips from Microchip Technology's:
   8  * 10 Bit converter
   9  * MCP3001
  10  * MCP3002
  11  * MCP3004
  12  * MCP3008
  13  * ------------
  14  * 12 bit converter
  15  * MCP3201
  16  * MCP3202
  17  * MCP3204
  18  * MCP3208
  19  * ------------
  20  * 13 bit converter
  21  * MCP3301
  22  *
  23  * Datasheet can be found here:
  24  * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf  mcp3001
  25  * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf  mcp3002
  26  * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf  mcp3004/08
  27  * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf  mcp3201
  28  * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf  mcp3202
  29  * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf  mcp3204/08
  30  * http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf  mcp3301
  31  *
  32  * This program is free software; you can redistribute it and/or modify
  33  * it under the terms of the GNU General Public License version 2 as
  34  * published by the Free Software Foundation.
  35  */
  36
  37 #include <linux/err.h>
  38 #include <linux/delay.h>
  39 #include <linux/spi/spi.h>
  40 #include <linux/module.h>
  41 #include <linux/iio/iio.h>
  42 #include <linux/regulator/consumer.h>
  43
  44 enum {
  45         mcp3001,
  46         mcp3002,
  47         mcp3004,
  48         mcp3008,
  49         mcp3201,
  50         mcp3202,
  51         mcp3204,
  52         mcp3208,
  53         mcp3301,
  54 };
  55
  56 struct mcp320x_chip_info {
  57         const struct iio_chan_spec *channels;
  58         unsigned int num_channels;
  59         unsigned int resolution;
  60 };
  61
  62 struct mcp320x {
  63         struct spi_device *spi;
  64         struct spi_message msg;
  65         struct spi_transfer transfer[2];
  66
  67         struct regulator *reg;
  68         struct mutex lock;
  69         const struct mcp320x_chip_info *chip_info;
  70
  71         u8 tx_buf ____cacheline_aligned;
  72         u8 rx_buf[2];
  73 };
  74
  75 static int mcp320x_channel_to_tx_data(int device_index,
  76                         const unsigned int channel, bool differential)
  77 {
  78         int start_bit = 1;
  79
  80         switch (device_index) {
  81         case mcp3001:
  82         case mcp3201:
  83         case mcp3301:
  84                 return 0;
  85         case mcp3002:
  86         case mcp3202:
  87                 return ((start_bit << 4) | (!differential << 3) |
  88                                                         (channel << 2));
  89         case mcp3004:
  90         case mcp3204:
  91         case mcp3008:
  92         case mcp3208:
  93                 return ((start_bit << 6) | (!differential << 5) |
  94                                                         (channel << 2));
  95         default:
  96                 return -EINVAL;
  97         }
  98 }
  99
 100 static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
 101                                   bool differential, int device_index, int *val)
 102 {
 103         int ret;
 104
 105         adc->rx_buf[0] = 0;
 106         adc->rx_buf[1] = 0;
 107         adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
 108                                                 channel, differential);
 109
 110         if (device_index != mcp3001 && device_index != mcp3201 && device_index != mcp3301) {
 111                 ret = spi_sync(adc->spi, &adc->msg);
 112                 if (ret < 0)
 113                         return ret;
 114         } else {
 115                 ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
 116                 if (ret < 0)
 117                         return ret;
 118         }
 119
 120         switch (device_index) {
 121         case mcp3001:
 122                 *val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
 123                 return 0;
 124         case mcp3002:
 125         case mcp3004:
 126         case mcp3008:
 127                 *val = (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
 128                 return 0;
 129         case mcp3201:
 130                 *val = (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
 131                 return 0;
 132         case mcp3202:
 133         case mcp3204:
 134         case mcp3208:
 135                 *val = (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
 136                 return 0;
 137         case mcp3301:
 138                 *val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
 139                                     | adc->rx_buf[1], 12);
 140                 return 0;
 141         default:
 142                 return -EINVAL;
 143         }
 144 }
 145
 146 static int mcp320x_read_raw(struct iio_dev *indio_dev,
 147                             struct iio_chan_spec const *channel, int *val,
 148                             int *val2, long mask)
 149 {
 150         struct mcp320x *adc = iio_priv(indio_dev);
 151         int ret = -EINVAL;
 152         int device_index = 0;
 153
 154         mutex_lock(&adc->lock);
 155
 156         device_index = spi_get_device_id(adc->spi)->driver_data;
 157
 158         switch (mask) {
 159         case IIO_CHAN_INFO_RAW:
 160                 ret = mcp320x_adc_conversion(adc, channel->address,
 161                         channel->differential, device_index, val);
 162                 if (ret < 0)
 163                         goto out;
 164
 165                 ret = IIO_VAL_INT;
 166                 break;
 167
 168         case IIO_CHAN_INFO_SCALE:
 169                 ret = regulator_get_voltage(adc->reg);
 170                 if (ret < 0)
 171                         goto out;
 172
 173                 /* convert regulator output voltage to mV */
 174                 *val = ret / 1000;
 175                 *val2 = adc->chip_info->resolution;
 176                 ret = IIO_VAL_FRACTIONAL_LOG2;
 177                 break;
 178         }
 179
 180 out:
 181         mutex_unlock(&adc->lock);
 182
 183         return ret;
 184 }
 185
 186 #define MCP320X_VOLTAGE_CHANNEL(num)                            \
 187         {                                                       \
 188                 .type = IIO_VOLTAGE,                            \
 189                 .indexed = 1,                                   \
 190                 .channel = (num),                               \
 191                 .address = (num),                               \
 192                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 193                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 194         }
 195
 196 #define MCP320X_VOLTAGE_CHANNEL_DIFF(num)                       \
 197         {                                                       \
 198                 .type = IIO_VOLTAGE,                            \
 199                 .indexed = 1,                                   \
 200                 .channel = (num * 2),                           \
 201                 .channel2 = (num * 2 + 1),                      \
 202                 .address = (num * 2),                           \
 203                 .differential = 1,                              \
 204                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 205                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 206         }
 207
 208 static const struct iio_chan_spec mcp3201_channels[] = {
 209         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 210 };
 211
 212 static const struct iio_chan_spec mcp3202_channels[] = {
 213         MCP320X_VOLTAGE_CHANNEL(0),
 214         MCP320X_VOLTAGE_CHANNEL(1),
 215         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 216 };
 217
 218 static const struct iio_chan_spec mcp3204_channels[] = {
 219         MCP320X_VOLTAGE_CHANNEL(0),
 220         MCP320X_VOLTAGE_CHANNEL(1),
 221         MCP320X_VOLTAGE_CHANNEL(2),
 222         MCP320X_VOLTAGE_CHANNEL(3),
 223         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 224         MCP320X_VOLTAGE_CHANNEL_DIFF(1),
 225 };
 226
 227 static const struct iio_chan_spec mcp3208_channels[] = {
 228         MCP320X_VOLTAGE_CHANNEL(0),
 229         MCP320X_VOLTAGE_CHANNEL(1),
 230         MCP320X_VOLTAGE_CHANNEL(2),
 231         MCP320X_VOLTAGE_CHANNEL(3),
 232         MCP320X_VOLTAGE_CHANNEL(4),
 233         MCP320X_VOLTAGE_CHANNEL(5),
 234         MCP320X_VOLTAGE_CHANNEL(6),
 235         MCP320X_VOLTAGE_CHANNEL(7),
 236         MCP320X_VOLTAGE_CHANNEL_DIFF(0),
 237         MCP320X_VOLTAGE_CHANNEL_DIFF(1),
 238         MCP320X_VOLTAGE_CHANNEL_DIFF(2),
 239         MCP320X_VOLTAGE_CHANNEL_DIFF(3),
 240 };
 241
 242 static const struct iio_info mcp320x_info = {
 243         .read_raw = mcp320x_read_raw,
 244         .driver_module = THIS_MODULE,
 245 };
 246
 247 static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
 248         [mcp3001] = {
 249                 .channels = mcp3201_channels,
 250                 .num_channels = ARRAY_SIZE(mcp3201_channels),
 251                 .resolution = 10
 252         },
 253         [mcp3002] = {
 254                 .channels = mcp3202_channels,
 255                 .num_channels = ARRAY_SIZE(mcp3202_channels),
 256                 .resolution = 10
 257         },
 258         [mcp3004] = {
 259                 .channels = mcp3204_channels,
 260                 .num_channels = ARRAY_SIZE(mcp3204_channels),
 261                 .resolution = 10
 262         },
 263         [mcp3008] = {
 264                 .channels = mcp3208_channels,
 265                 .num_channels = ARRAY_SIZE(mcp3208_channels),
 266                 .resolution = 10
 267         },
 268         [mcp3201] = {
 269                 .channels = mcp3201_channels,
 270                 .num_channels = ARRAY_SIZE(mcp3201_channels),
 271                 .resolution = 12
 272         },
 273         [mcp3202] = {
 274                 .channels = mcp3202_channels,
 275                 .num_channels = ARRAY_SIZE(mcp3202_channels),
 276                 .resolution = 12
 277         },
 278         [mcp3204] = {
 279                 .channels = mcp3204_channels,
 280                 .num_channels = ARRAY_SIZE(mcp3204_channels),
 281                 .resolution = 12
 282         },
 283         [mcp3208] = {
 284                 .channels = mcp3208_channels,
 285                 .num_channels = ARRAY_SIZE(mcp3208_channels),
 286                 .resolution = 12
 287         },
 288         [mcp3301] = {
 289                 .channels = mcp3201_channels,
 290                 .num_channels = ARRAY_SIZE(mcp3201_channels),
 291                 .resolution = 13
 292         },
 293 };
 294
 295 static int mcp320x_probe(struct spi_device *spi)
 296 {
 297         struct iio_dev *indio_dev;
 298         struct mcp320x *adc;
 299         const struct mcp320x_chip_info *chip_info;
 300         int ret;
 301
 302         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 303         if (!indio_dev)
 304                 return -ENOMEM;
 305
 306         adc = iio_priv(indio_dev);
 307         adc->spi = spi;
 308
 309         indio_dev->dev.parent = &spi->dev;
 310         indio_dev->name = spi_get_device_id(spi)->name;
 311         indio_dev->modes = INDIO_DIRECT_MODE;
 312         indio_dev->info = &mcp320x_info;
 313         spi_set_drvdata(spi, indio_dev);
 314
 315         chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
 316         indio_dev->channels = chip_info->channels;
 317         indio_dev->num_channels = chip_info->num_channels;
 318
 319         adc->chip_info = chip_info;
 320
 321         adc->transfer[0].tx_buf = &adc->tx_buf;
 322         adc->transfer[0].len = sizeof(adc->tx_buf);
 323         adc->transfer[1].rx_buf = adc->rx_buf;
 324         adc->transfer[1].len = sizeof(adc->rx_buf);
 325
 326         spi_message_init_with_transfers(&adc->msg, adc->transfer,
 327                                         ARRAY_SIZE(adc->transfer));
 328
 329         adc->reg = devm_regulator_get(&spi->dev, "vref");
 330         if (IS_ERR(adc->reg))
 331                 return PTR_ERR(adc->reg);
 332
 333         ret = regulator_enable(adc->reg);
 334         if (ret < 0)
 335                 return ret;
 336
 337         mutex_init(&adc->lock);
 338
 339         ret = iio_device_register(indio_dev);
 340         if (ret < 0)
 341                 goto reg_disable;
 342
 343         return 0;
 344
 345 reg_disable:
 346         regulator_disable(adc->reg);
 347
 348         return ret;
 349 }
 350
 351 static int mcp320x_remove(struct spi_device *spi)
 352 {
 353         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 354         struct mcp320x *adc = iio_priv(indio_dev);
 355
 356         iio_device_unregister(indio_dev);
 357         regulator_disable(adc->reg);
 358
 359         return 0;
 360 }
 361
 362 #if defined(CONFIG_OF)
 363 static const struct of_device_id mcp320x_dt_ids[] = {
 364         {
 365                 .compatible = "mcp3001",
 366                 .data = &mcp320x_chip_infos[mcp3001],
 367         }, {
 368                 .compatible = "mcp3002",
 369                 .data = &mcp320x_chip_infos[mcp3002],
 370         }, {
 371                 .compatible = "mcp3004",
 372                 .data = &mcp320x_chip_infos[mcp3004],
 373         }, {
 374                 .compatible = "mcp3008",
 375                 .data = &mcp320x_chip_infos[mcp3008],
 376         }, {
 377                 .compatible = "mcp3201",
 378                 .data = &mcp320x_chip_infos[mcp3201],
 379         }, {
 380                 .compatible = "mcp3202",
 381                 .data = &mcp320x_chip_infos[mcp3202],
 382         }, {
 383                 .compatible = "mcp3204",
 384                 .data = &mcp320x_chip_infos[mcp3204],
 385         }, {
 386                 .compatible = "mcp3208",
 387                 .data = &mcp320x_chip_infos[mcp3208],
 388         }, {
 389                 .compatible = "mcp3301",
 390                 .data = &mcp320x_chip_infos[mcp3301],
 391         }, {
 392         }
 393 };
 394 MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
 395 #endif
 396
 397 static const struct spi_device_id mcp320x_id[] = {
 398         { "mcp3001", mcp3001 },
 399         { "mcp3002", mcp3002 },
 400         { "mcp3004", mcp3004 },
 401         { "mcp3008", mcp3008 },
 402         { "mcp3201", mcp3201 },
 403         { "mcp3202", mcp3202 },
 404         { "mcp3204", mcp3204 },
 405         { "mcp3208", mcp3208 },
 406         { "mcp3301", mcp3301 },
 407         { }
 408 };
 409 MODULE_DEVICE_TABLE(spi, mcp320x_id);
 410
 411 static struct spi_driver mcp320x_driver = {
 412         .driver = {
 413                 .name = "mcp320x",
 414                 .of_match_table = of_match_ptr(mcp320x_dt_ids),
 415         },
 416         .probe = mcp320x_probe,
 417         .remove = mcp320x_remove,
 418         .id_table = mcp320x_id,
 419 };
 420 module_spi_driver(mcp320x_driver);
 421
 422 MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
 423 MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
 424 MODULE_LICENSE("GPL v2");